We do not have a complete explanation of why the crossover between modes is sharper in \(I_C\)  then in \(G_N\) . The description above by a difference in confinement ratios suggests that the shape of the constriction is not the same in the normal and superconducting states (that it is effectively narrower and/or longer in the latter). An alternate explanation could involve partial breakdown of the assumption that the the constriction is adiabatically coupled to the leads [1]}, [2]}, and a different extent of this breakdown in the normal and superconducting states.
